Russia is designing a new SSBN (nuclear ballistic missile submarine). The Russians continue to build SSNs (nuclear attack submarines) and are building the first diesel-electric sub of the Lada class. This boat, the Sankt Peterburg weighs 1675 tons. This is a follow on to the Kilo class. The new boats are to be much quieter than the Kilos. A variant on the Ladas, the Amur class, are being offered for export. These will not have all the latest silencing technology of the Ladas, so as not to compromise the best Russian silencing technology.